NTT DoCoMo and Mitsubishi Electric announced today, at a hastily called press conference, that some D06-series batteries, which were manufactured through May 2006 and installed in the D902i-series handsets, could generate excessive heat and possibly rupture during charging if the batteries have been subjected to a strong external impact. The companies estimate that some 1.3 million D06 series batteries were manufactured through May 2006. Sales of the D902i, D902iS and D903i have been suspended for the time being.
According to the press release, the problem is due to deformed electrode plates installed in the batteries. If the batteries are accidentally subjected to a strong external impact that results in a surface dent or similar depression, the deformed plates could pierce the batteries’ internal insulation, resulting in an electrical short during, or right after, charging.
To date, DoCoMo has confirmed that one D06 battery has ruptured due to the problem. In addition, 17 other cases of D06 battery rupture or overheating have been reported. So far, DoCoMo has confirmed that in a number of these cases, the malfunctioning batteries had been subjected to extremely strong impact. The other cases are still being investigated.
All D902i handsets owners will be directly mailed letters informing them that they will receive replacement batteries. Also, owners of D902iS and D903i handsets, which may possibly be equipped with the defective D06 batteries, will be directly mailed letters alerting them to check if their batteries bear any of the specified three-letter codes. Replacement batteries will then be sent to users accordingly. The labels on these batteries bear one of the following clearly marked three-letter codes: OKA, OLA, PAA, PBA, PCA, PDA or PEA.